WASHINGTON, D.C. — A Texas charitable organization says about 30 immigrant parents separated from their children after crossing the U.S.-Mexico border were freed into its care Sunday, but they don’t know where their kids are or when they might see them again despite government assurances that family reunification would be well organized.

The release is believed to be the first, large one of its kind since President Donald Trump signed an executive order Wednesday that preserved a “zero-tolerance” policy for entering the country illegally but ended the practice of separating immigrant parents and children. U.S. Immigration and Customs Enforcement offered no immediate comment.

Ruben Garcia, director of Annunciation House in El Paso, says the parents arrived to his group after federal authorities withdrew criminal charges for illegal entry. He didn’t release names or personal details to protect the parents’ privacy, and Homeland Security officials said they needed more specifics in order to check out their cases.

A Saturday night fact sheet by the Department of Homeland Security and other agencies said authorities know the location of all children in custody after separating them from their families at the border and are working to reunite them. It called the reunification process “well coordinated.”

It also said parents must request that their child be deported with them. In the past, the fact sheet says, many parents elected to be deported without their children. That may be a reflection of violence or persecution they face in their home countries.

It doesn’t state how long it might take to reunite families. Texas’ Port Isabel Service Processing Center has been set up as the staging ground for the families to be reunited prior to deportation.

How the government would reunite families has been unclear because they are first stopped by U.S. Customs and Border Patrol, with children taken into custody by the Department of Health and Human Services and adults detained through ICE, which is under the Department of Homeland Security. Children have been sent to far-flung shelters around the country, raising alarm that parents might never know where their children can be found.

At least 2,053 minors who were separated at the border were being cared for in HHS-funded facilities, the fact sheet said.

The chairman of the Senate Homeland Security Committee hedged Sunday when pressed on whether he was confident the Trump administration knows where all the children are and will be able to reunite them with their parents.

“That is what they’re claiming,” Sen. Ron Johnson, R-Wis., said on CNN’s “State of the Union.”

The fact sheet states that ICE has implemented an identification mechanism to ensure ongoing tracking of linked family members throughout the detention and removal process; designated detention locations for separated parents and will enhance current processes to ensure communication with children in HHS custody; worked closely with foreign consulates to ensure that travel documents are issued for both the parent and child at time of removal; and coordinated with HHS for the reuniting of the child prior to the parents’ departure from the U.S.

As part of the effort, ICE officials have posted notices in all its facilities advising detained parents who are trying to find or communicate with their children to call a hotline staffed 8 a.m. to 8 p.m. Monday through Friday.

A parent or guardian trying to determine if a child is in the custody of HHS should contact the Office of Refugee Resettlement National Call Center at 1-800-203-7001, or via email at information@ORRNCC.com. Information will be collected and sent to an HHS-funded facility where a minor is located.

But it’s unclear whether detained parents have access to computers to send an email, or how their phone systems work to call out. Attorneys at the border have said they have been frantically trying to locate information about the children on behalf of their clients.

Garcia, the Annunciation House director, said his experience has been that telephone contact doesn’t provide any information.

“If we bring in 30 cellphones, they’re going to call that number, they’re not going to reach 30 children,” said Garcia, whose organization has been working with federal authorities to assist immigrants for 40 years. “Actually (they’re) not going to be able to give them any information on what to expect.”

Customs and Border Patrol said it had reunited 522 children and that some were never taken into custody by Health and Human Services because their parents’ criminal cases were processed too quickly. Officials have said as many as 2,300 children had been separated from the time the policy began until June 9. It’s not clear if any of the 2,000 remaining children were taken into custody after June 9.

The “zero-tolerance policy” of criminally prosecuting anyone caught illegally crossing the border remains in effect, officials have said, despite confusion on the ground on how to carry out President Trump’s order. Justice Department officials asked a federal judge to amend a class-action settlement that governs how children are treated in immigration custody. Right now, children can only be detained with their families for 20 days; President Trump officials are seeking to detain them together indefinitely as their cases progress. Advocates say family detention does not solve the problem.